Carrier for disk drive hot swapping

ABSTRACT

In general the invention features a disk drive carrier and a method for inserting a disk drive into a peripheral bay chassis. The disk drive carrier includes a base for receiving a disk drive into and a latching mechanism that is rotatably attached to the base. The rotatably mount permits a lever to rotate between an open position and a closed position. The lever includes a lower engagement point and an upper engagement point. The disk drive carrier can additionally include a downwardly movable release tab attached to the upper engagement point facilitating release of the engagement point from a P-Bay chassis. The disk drive carrier can also include an electromagnetic interference (EMI) shield to create a tight EMI seal in the front of a P-Bay chassis slot.

BACKGROUND OF THE INVENTION

This invention relates to disk drive hot swapping. PC networks and, inparticular, client server technology have created a need for networkservers comprising relatively large and fast processors and randomaccess memory coupled to an expandable array of large, fast hard drives.The hard drives provide non-volatile storage for application programsand data. One efficient method of providing for non-volatile storage isthrough an array of relatively inexpensive disk drives that can act inconcert to provide nonvolatile storage that is faster and more reliablethan a single, large, expensive hard disk drive.

One technology that enables inexpensive hard drives to cooperate isgenerally known as a redundant array of inexpensive disks or RAID and isparticularly useful in the environment of network servers. RAID providesdata redundancy such that if a single disk drive fails, lost data can bereconstructed from data stored on the remaining disks. In addition,multiple hard drives can be mirrored whereby copies of applicationprograms and data are simultaneously stored on multiple disks. In theevent of disk failure, a mirror image of a failed drive is available onanother disk.

A RAID can be monitored and in the event of a disk drive failure, thefailed disk can be replaced and data restored without interrupting theoperation of a server. In addition, an operational disk drive can beremoved and archived at the same or a remote location. An archived diskdrive can also be replaced without interrupting the operation of aserver. In order to replace a hard drive while the system isoperational, a disk drive is “hot swapped,” the term “hot” referring tolive voltage and signals being applied to the drive while it is beingremoved and replaced.

Typically, a RAID is housed in a peripheral bay chassis (P-Bay). A P-Baychassis can efficiently arrange hard drives and supply them with power,control and data connections, while allowing for adequate cooling ofhard drives housed within it. A computer can be electrically connectedto the P-Bay and thereby be given the advantages of having multiple diskdrives.

Hard drives have been known to be mounted into a P-Bay chassis bybolting the drive into the chassis, using a cam driven handle to insertthe drive into the chassis and other mechanisms. To limit vibrationaleffects, each hard drive needs to be securely mounted into the chassis.

SUMMARY

In general the invention features a disk drive carrier and a method forinserting a disk drive into a peripheral bay chassis. In one aspect ofthe invention the disk drive carrier includes a base for receiving adisk drive and a latching mechanism rotatably attached to the basepermitting a lever to rotate between an open position and a closedposition. The lever includes a lower engagement point and an upperengagement point.

In general, in another aspect, the invention features a base formounting a disk drive. The base includes a channel formed with an uppersurface and a substantially flat interior. The base also includes alower surface with a substantially flat interior and a side wall with afinned exterior.

In general, in another aspect, the invention features an electromagneticinterference (EMI) shield. The EMI shield can include a multi-ventholefrontal plate connected at a substantially right angle to a side panel.

In general, in another aspect, the invention includes a method forinserting a disk drive into a peripheral bay chassis. The method caninclude the steps of receiving a disk drive into a base of a disk drivecarrier and inserting the carrier into a peripheral bay chassis slotwhile a lever is in an open position. The lever can then be rotated tothe closed position to engage the peripheral bay chassis with the lowerengagement point and the upper engagement point.

Other features and advantages of the invention will be apparent from thedescription, drawings and claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1(a) and FIG. 1(b) are isometric views of an assembled carrier.

FIG. 2(a) and FIG. 2(b) are views of a latching mechanism.

FIG. 3 is a profile perspective of a latching mechanism.

FIG. 4 is an EMI shield.

FIG. 5(a) and FIG. 5(b) are views of a base.

FIG. 6 is a carrier assembly including a hard drive.

FIG. 7 is an isometric view of a P-Bay chassis with carriers.

FIG. 8 is a frontal view of a P-Bay chassis with carriers.

DETAILED DESCRIPTION

FIG. 1 illustrates a server disk drive carrier assembly 100. The diskdrive carrier assembly includes a latching mechanism 200, anelectromagnetic interference (EMI) shield 400 and a base 500.

The base 500 holds a computer disk drive and serves as a heat sink todissipate heat generated by the disk drive. The base 500 typicallycomprises an electrically and thermally conductive material such asaluminum and is formed to provide a channel that matches the size andshape of a hard drive. Referring also to FIG. 5, the base can be formedso that the channel has a substantially flat interior upper surface 524;a substantially flat interior lower surface 520; and a side wall with afinned exterior 510 and a contoured interior surface 522. Referring alsoto FIG. 6, the contoured interior side surface 522 compliments theexterior contour of a hard drive 625 that can be mounted between theupper surface 524 and lower surface 520. The finned exterior 510 aids indissipating heat. To maximize heat transfer from a drive to the base thehard drive may be mounted within the base in contact with interior uppersurface 524, interior lower surface 520 and interior side surface 522.

A computer disk drive 625 can be secured to the base with one or morefasteners such as flat head machine screws 514 inserted through mountingholes 511 formed into the base and set into the drive 625. Forming abase from an electrically conductive material is useful for grounding ahard drive 625 mounted therein and acting as an electrical path todissipate electrostatic charges that may build up near the drive 625. Anelectrical path from the base 500 to a grounded P-Bay chassis 700 (FIG.7) can be provided through metal retention clips 610 inserted intoretention clip slots 515 formed into the base 500. The retention clips610 can also hold a base into a P-Bay chassis 700 and provide increasedvibration control.

As seen in FIGS. 2 and 3, latching mechanism 200 comprising upper andlower locking points for holding the base in a P-Bay chassis is securelyattached to one end of the base. The lower locking point comprises anengagement lug 210 and the upper locking point comprises at least twoengagement shoulders 220. The latching mechanism can form a carrierhandle 240 and be attached to the base 500 using one or more fastenerssuch as a machine screw 516 inserted through a hole 255 and set into thebase 500. The carrier handle can be ergonomic in design to facilitateease of use.

The latching mechanism 200 has a lever 242 rotatably mounted on a pivot260 so as to rotate between an open position 241 and a closed position251. In one example a lever 242 in a fully open position 241 is orientedat 90° from a fully closed position 251. Lower engagement lug 210 andthe upper engagement shoulders 220 project in opposite directions fromopposite ends of the lever. The lower engagement lug 210 and the upperengagement shoulder 220 may be offset from the rotatable mount 260. Anoffset causes a general U shape in the handle as a path through itslower engagement hug 210, the pivot point 260 and the upper engagementshoulder 220 is not linear.

The lower engagement lug 210 mates with a lower cutout 710 in a P-Baychassis 700, securing the carrier 100 into the P-Bay chassis 700 whenthe lever 242 is in the closed position 251. In one embodiment, thelower engagement lug 210 engages the lower cutout 710 while the lever242 is less than fully closed.

The upper engagement shoulder 220 is attached to the top of a releasetab 230. The release tab 230 is flexibly secured to the lever 242 anddownwardly movable. A lower release tab stop plate 231 limits thedownward motion of the release tab 230, and can also serve as a fingerhold. An upper stop point 232 limits the upward movement of the releasetab. The upper engagement shoulder can engage an upper cutout 720 in aP-Bay chassis while the lever is in a closed position 251. A downwardpressure on the release tab 230 causes downward movement by the tab 330and the upper engagement shoulders 220. Downward motion can cause theupper engagement shoulder 220 to disengage from the upper cutout 720 ofthe P-Bay chassis 700. If the upper engagement shoulder 220 isdisengaged from the upper cutout 720, the lever 242 is released and canbe moved into an open position 241.

Latching mechanism 200 may be formed from a plastic such as ABS orpolycarbonate plastic. The latching mechanism can be economically formedusing injection molding. The lower engagement lug 210, the upperengagement shoulder 220, the release tab 230, the release tab stop plate231 and the lever 242 can all be formed from one piece of contiguousmolded plastic. A second piece of molded plastic can comprise the handle240 and securement pads 250 and be attached to the first piece of moldedplastic via a rotatable mount 260 such as a pin or other hingeapparatus. The pin can also comprise ABS or polycarbonate plastic.

Shoulder slots 248 can be formed in the upper handle 240 to allow theengagement shoulders 220 to reach a fully closed position 251. Theshoulder slots 248 can also serve to limit lateral movement of thelatching mechanism lever 242 while the latching mechanism lever 242 isin the closed position 251. Each engagement shoulder 220 formed into thelever 242 should have a corresponding slot 248 formed into the handle.

The electromagnetic interference (EMI) shield 400 is mounted between thelatching mechanism 200 and the base 500 and substantially perpendicularto the base 500. When the carrier 100 is inserted into a P-Bay chassis700, the EMI shield 400 effectively creates a tight EMI seal in thefront of the P-Bay chassis slot 800 by spanning any empty space andcontacting an adjacent drive. Use of an EMI shield 400 can reduce theneed for a separate EMI door on the chassis. The EMI shield 400comprises an electrically conductive metal such as steel formed into afront panel 420 and a side panel 430. The side panel 430 is essentiallyperpendicular to the front panel 420. The panels can have vent holes 421to allow airflow through the EMI shield 400, the airflow being conduciveto cooling an operational disk drive 625 mounted in the carrier 100. Thevent holes do not affect EMI shielding properties. The EMI shield can bemounted to the base with a fastener such as a machine screw through anEMI shield mounting hole 415 or other known fastening means, such asriveting.

The EMI shield 400 can be grounded to the chassis with one or morefinger clips 410 mounted in finger clip slots 425. The finger clip slots425 are formed into the side panel 430. The finger clips can befashioned from an electrically conductive material with spring likecharacteristics, such as stainless spring steel. Generally, the fingerclips form a spring loaded arc that compresses when perpendicularpressure is applied to the arc. As a carrier 100 is inserted into aP-Bay chassis 700, a finger clip 410 contacts the chassis 700 or anadjacent carrier and compresses. The force of the compression againstthe contact point causes a mechanical and electrical connection. Themechanical connection provides additional stability to the drive. Theelectrical connection provides a low insertion force ground to thecarrier 100 and hard drive 625 mounted therein while the carrier 100 isbeing inserted into the chassis 200 and before a disk drive 625connector mates with a high speed back plane (HSBP) 810. Grounding thecarrier 100 before contact with the HSBP 810 provides a conductive pathproviding for electrostatic discharge into the chassis 700 instead ofthe HSBP 810. The finger clips 410 may be replaceable to extend theuseful life of the EMI shield 400.

A user can install a hard drive 625 into a P-Bay chassis by mounting anoriginal equipment manufacturer (OEM) disk drive into the base 500. Inone embodiment the disk drive 625 is mounted using two screws 514through the upper surface 524 of the base 500 and two screws 514 throughthe lower surface 520 of the base 500. The carrier is inserted 730 intoa P-Bay chassis slot 800 with the lever 242 in an open position (leveris at an angle greater than 0° and less than 90° to the carrier handle).A user can depress the release tab 230 by applying downward pressure,and fully insert the carrier 100 into the P-Bay chassis 700 causing thedisk drive connector 626 to engage with the HSBP 810. The user can thenmove the lever 242 into the closed position (˜0°). As the lever 242 isclosed the lower engagement lug 210 will insert into a lower cutout 710latching the bottom of the carrier 100. The user allows the release tab230 to return up to its rest position causing the upper engagementshoulder 220 to engage an upper cutout 720 thereby latching the top ofthe carrier to the P-Bay chassis 700. As the carrier 100 proceeded intothe P-Bay chassis 700, the finger clips 410 tightly contact an adjacentcarrier in an adjacent P-Bay chassis slot 800 grounding the carrier 100before the disk drive connector engaged the HSBP 810.

The invention may provide advantages that include improved vibrationcontrol, ease of use for a technician swapping drives, limitedhorizontal movement of a carrier, excellent EMI shielding and lessrestricted air flow for cooling of disk drives.

Other embodiments are within the scope of the following claims.

What is claimed is:
 1. A disk drive carrier comprising: a base for receiving a disk drive, said base spanning a height between a lowermost exposed surface of the base and an uppermost exposed surface of the base; and a latching mechanism rotatably attached to the base permitting a lever to rotate between an open position and a closed position, the lever comprising: a body having a length; a lower engagement point configured to secure said base to an engagement feature of a chassis; and an upper engagement point extending beyond the length of the lever body and extending, when the latching mechanism is in the closed position, beyond the uppermost surface of the base and configured to secure said base to a corresponding engagement feature of the chassis.
 2. The disk drive carrier of claim 1 additionally comprising a release tab attached to the upper engagement point, said release tab being downwardly movable.
 3. The disk drive carrier of claim 1 wherein the lower engagement point comprises a lug.
 4. The disk drive carrier of claim 1 wherein the upper engagement point comprises a shoulder.
 5. The disk drive carrier of claim 1 additionally comprising a securement pad attached to the latching mechanism.
 6. The disk drive carrier of claim 1 additionally comprising a handle calculating carrier insertion into the chassis, the handle being attached to the lever.
 7. The disk drive carrier of claim 1 wherein the latching mechanism is formed of molded plastic.
 8. The disk drive carrier of claim 1 wherein the latching mechanism comprises polycarbonate plastic. 